The mk1 non-vvti engine is a lot cheaper and as its stands easier to mod engine of the two. Most tuning parts will be cross compatable but from what i can tell clearance issues around the suspension towers will be one area that could cause you problems with turbo fitments. As for power if you don't want huge power ie over 400 at the wheels then the stock turbo's will suffice. My supra (I know I know I harp on about it lol) is pushing at least 370 bhp at the wheels with 1.2 bar of boost. Stock tubbies, walbro fuel pump, stock injectors, front mount intercooler, water injection, hks 264 inlet and exhaust cams, FCD, FSE, boost controller, full decat and sports exhaust. A set of hybrids (stock tubby housing with uprated twin impellors) will sort you for 1.5 bar of boost, couple them with 550 injectors and you could push up to 410 at the wheels. Above that you are looking at single or if you can get it big twins. Have a look at the supraforums for an indication of what can be done.